The present invention relates to the field of cementitious materials such as Portland Cement and geopolymers. The purpose of the invention is to apply divalent magnesium-iron solid solution silicates (for example the mineral groups olivine, orthopyroxene, amphibole, talc and serpentine), here called “magnesium silicates”, as latent hydraulic binders for cementitious mineral admixtures, thereby increasing the integrity, volume, weathering and/or lifetime of the cementitious mineral admixture structure.
The invention relates the integrity- and/or durability enhancement of cementitious structures over time by including/adding magnesium silicates in cementitious mineral admixtures as a latent hydraulic binder, and to increase its capacity to handle weathering and exposure to flow of water mixtures on and through the cementitious materials.
Ordinary well cement is based on the principles of Portland Cement. As NORSOK D010 and API Spec 10A are the current industrial standards for operations in the oil and gas industry, it was important that that the present invention is able to meet those standards in an affordable manner. Of particular advantage of the present invention is that it easily added to current well cements operations to improve performance and meet standards. Many of the advantages of the present invention are apparent in the application of well cementing and completing, plugging, temporary and permanent abandonment of wells
Alternatives proposed to ordinary well cements are Geopolymers. These are materials that are visco-elastic. An example of this physical property is the mixture of cornflour and water; it is hard when handled and soft when held. Another example is Bingham Plastic. This behaves like mayonnaise (soft when handled, hard when held). Neither of these products are currently reasonably priced or particularly standard friendly.
Metamorphism is the mineralogical and structural adjustment of solid rocks to physical and chemical conditions that have been imposed at depths below the near surface zones of weathering and diagenesis and which differ from conditions under which the rocks in question originated.
Inorganic materials that have pozzolanic or latent hydraulic binding effects are commonly used in cementitious materials. Hydraulicity is defined as “the property of limes and cements to set and harden under water whether derived from a naturally hydraulic lime, cement or a pozzolan”. A latent hydraulic binder reacts in more slowly and due to a trigger in a particular manner in order to change the properties of the cementitious products. It will come to a full strength on its own, while very slowly. These have the purpose of either stretching the need for lime clinker in the cementitious mineral admixture, or improve the properties of the cementitious mineral admixture.